[OpenMP] Add interface for 5.1 scope construct

[hbae]

Summary

The new interface only marks begin/end of a scope construct for
corresponding OMPT events, and we can use existing interfaces for
reduction operations.

[AndreyChurbanov]

LGTM

openmp/runtime/src/dllexports

# USED ABOVE __kmpc_critical_with_hint    270
         __kmpc_task_reduction_modifier_fini 275
         __kmpc_task_allow_completion_event  276
         __kmpc_taskred_init                 277
         __kmpc_taskred_modifier_init        278
         __kmpc_omp_target_task_alloc        279
         __kmpc_error                        281
         __kmpc_masked                       282
         __kmpc_end_masked                   283
+        __kmpc_scope                        286
+        __kmpc_end_scope                    287
 %endif
 
 # User API entry points that have both lower- and upper- case versions for Fortran.
 # Number for lowercase version is indicated.  Number for uppercase is obtained by adding 1000.
 # User API entry points are entry points that start with 'kmp_' or 'omp_'.
 
 omp_destroy_lock                            700
 omp_destroy_nest_lock                       701

openmp/runtime/src/kmp.h

 
 // Support for error directive
 typedef enum kmp_severity_t {
   severity_warning = 1,
   severity_fatal = 2
 } kmp_severity_t;
 extern void __kmpc_error(ident_t *loc, int severity, const char *message);
 
+// Support for scope directive
+KMP_EXPORT void __kmpc_scope(ident_t *loc, kmp_int32 gtid, void *reserved);
+KMP_EXPORT void __kmpc_end_scope(ident_t *loc, kmp_int32 gtid, void *reserved);
+
 #ifdef __cplusplus
 }
 #endif
 
 template <bool C, bool S>
 extern void __kmp_suspend_32(int th_gtid, kmp_flag_32<C, S> *flag);
 template <bool C, bool S>
 extern void __kmp_suspend_64(int th_gtid, kmp_flag_64<C, S> *flag);

openmp/runtime/src/kmp_csupport.cpp

#endif // OMPT_SUPPORT
   if (severity == severity_warning)
     KMP_WARNING(UserDirectedWarning, src_loc, message);
   else
     KMP_FATAL(UserDirectedError, src_loc, message);
 
   __kmp_str_free(&src_loc);
 }
 
+// Mark begin of scope directive.
+void __kmpc_scope(ident_t *loc, kmp_int32 gtid, void *reserved) {
+// reserved is for extension of scope directive and not used.
+#if OMPT_SUPPORT && OMPT_OPTIONAL
+  if (ompt_enabled.enabled && ompt_enabled.ompt_callback_work) {
+    kmp_team_t *team = __kmp_threads[gtid]->th.th_team;
+    int tid = __kmp_tid_from_gtid(gtid);
+    ompt_callbacks.ompt_callback(ompt_callback_work)(
+        ompt_work_scope, ompt_scope_begin,
+        &(team->t.ompt_team_info.parallel_data),
+        &(team->t.t_implicit_task_taskdata[tid].ompt_task_info.task_data), 1,
+        OMPT_GET_RETURN_ADDRESS(0));
+  }
+#endif // OMPT_SUPPORT && OMPT_OPTIONAL
+}
+
+// Mark end of scope directive
+void __kmpc_end_scope(ident_t *loc, kmp_int32 gtid, void *reserved) {
+// reserved is for extension of scope directive and not used.
+#if OMPT_SUPPORT && OMPT_OPTIONAL
+  if (ompt_enabled.enabled && ompt_enabled.ompt_callback_work) {
+    kmp_team_t *team = __kmp_threads[gtid]->th.th_team;
+    int tid = __kmp_tid_from_gtid(gtid);
+    ompt_callbacks.ompt_callback(ompt_callback_work)(
+        ompt_work_scope, ompt_scope_end,
+        &(team->t.ompt_team_info.parallel_data),
+        &(team->t.t_implicit_task_taskdata[tid].ompt_task_info.task_data), 1,
+        OMPT_GET_RETURN_ADDRESS(0));
+  }
+#endif // OMPT_SUPPORT && OMPT_OPTIONAL
+}
+
 #ifdef KMP_USE_VERSION_SYMBOLS
 // For GOMP compatibility there are two versions of each omp_* API.
 // One is the plain C symbol and one is the Fortran symbol with an appended
 // underscore. When we implement a specific ompc_* version of an omp_*
 // function, we want the plain GOMP versioned symbol to alias the ompc_* version
 // instead of the Fortran versions in kmp_ftn_entry.h
 extern "C" {
 // Have to undef these from omp.h so they aren't translated into